America and Taiwan Had a Secret Transport Squadron in Vietnam

Covert unit dropped agents into the Communist North

Six specially-modified U.S. Air Force C-123 transport planes with Taiwanese aircrews flew some of the most secret missions of the Vietnam War. The C-123s...

Six specially-modified U.S. Air Force C-123 transport planes with Taiwanese aircrews flew some of the most secret missions of the Vietnam War. The C-123s arrived at Nha Trang, South Vietnam, in the summer of 1964.

The Air Force established the First Flight Detachment primarily to parachute agents behind enemy lines as part of OPLAN 34A-64. This over-arching operation was a top-secret American and South Vietnamese effort to infiltrate the North and harass the Communists.

The operatives were supposed to gather intel, spread rumors and sabotage key infrastructure. The entire effort fell under the euphemistically-titled Studies and Observation Group—a.k.a., SOG—closely cooperating with the Central Intelligence Agency.

The planes also dropped supplies to teams already on the ground. First Flight eventually took on other missions, such as dropping propaganda leaflets.

The Republic of China Air Force crews gave the missions—nicknamed Heavy Hook—some plausible deniability. Washington had started its covert operations before the Gulf of Tonkin Resolution provided any legal framework for the intervention in Vietnam.

The Heavy Hook planes lacked any national markings. Special brackets allowed ground crews to slot in different insignias in if they were needed.

Heavy Hook’s C-123s also had special radars to help them fly low at night—and countermeasures to protect them from enemy air defenses. The planes wore special dark camouflage to further hide them.

The official line was that the aircraft were on loan from South Vietnam to Taiwan. Crews were supposed to blame navigation errors if anyone spotted the planes flying over the North … or shot them down.

The Chinese fliers carried fake South Vietnamese documents, but the Americans instructed them to identify themselves as China Airlines employees, if captured. Agents on board were to claim they were on their way to Taiwan for military training.

The flying branch—and the U.S. Army Air Forces before it—had performed these kinds of missions since World War II. First Flight built on years of previous experience.

Still, the ad hoc and international nature of the program caused some significant issues. American commanders at the Pentagon, in the Pacific and in Vietnam held differing views on the whole enterprise.

For one, SOG and the CIA had chosen the twin-engined C-123 aircraft—depicted here—mostly because they were available. Originally designed as unpowered gliders, the planes lacked the range of the four-engine C-130 and couldn’t carry as much cargo.

To solve this problem, in 1965 the Air Force began work on a dedicated special operations transport. But in the meantime, SOG had to rely on First Flight’s planes and Chinese crews.

The foreign component further complicated matters. Any problems with the Taiwanese pilots and crew effectively halted operations.

A plan to train Vietnamese personnel for the missions ended in almost complete failure—trainees even crashed one of the planes into a mountain. The highly political South Vietnamese air force had selected candidates based on patronage and snatched them away for other operations with little notice.

By 1968, American commanders in the Pacific and Vietnam asked the Pentagon to finally cancel the Taiwanese contract. SOG felt that the new modified C-130s and their American crews could do the job just fine by themselves.

But Washington worried about insulting Taipei—and refused. The four remaining Heavy Hook transports soldiered on in Vietnam until 1972.

In the end, the U.S. gave the Heavy Hook C-123s to Taiwan, which possibly flew them on secret missions over mainland China. One of the planes is on display—with a less ominous paint job—at the Taiwanese air force museum.

The U.S. Air Force’s specialized C-130s, on the other hand, became the progenitors of today’s Air Commando MC-130s.